In the span of just a couple years, five of Heather Buren’s colleagues at the San Francisco Fire Department were diagnosed with breast cancer. At first, Buren thought the diagnoses were part of the unfortunate toll that comes with age. Still, something felt amiss — “it just felt so disproportionate to me,” she said.

Around the same time, Buren helped a good friend and mentor within the department as she underwent a double mastectomy. Buren said it was at that moment that she decided to take decisive action.

“(The cancer) just brought her to her knees,” she told me. “Now she’s good and back in the field. But in that moment when I saw this happening to her, I thought, ‘What’s going on? These are the fittest, strongest, healthiest women I know. What’s happening?’”

The experience compelled Buren to reach out to the San Francisco Firefighters Cancer Prevention Foundation, which in 2012, partnered with United Fire Service Women and a number of environmental health and cancer advocates to investigate growing concerns about premenopausal breast cancer cases within the fire department. The result was the grant-funded Women Firefighter Biomonitoring Collaborative Study, the first study of its kind to measure chemical exposures, including those chemicals linked to breast cancer, among women firefighters.

“My goal is to find out what’s going on and then, hopefully, start to change our standard operating procedure,” said Buren, one of four principal investigators on the study, a study participant and a lieutenant within the San Francisco Fire Department. “I’ve been a firefighter for 18 years and there’s things we can control and there’s so much we can’t control. I can’t choose whether or not I fight a fire, but there may be ways we can better protect ourselves from potential exposures.”

The San Francisco Fire Department is particularly well suited for this type of study, as it’s home to the largest number of women firefighters — about 225 — in the nation. Currently, the collaborative is in the midst of collecting blood and urine samples as well as gathering health and behavioral information from 80 San Francisco women firefighters and 80 city office workers, who will serve as the study’s control group. Buren said the collaborative hopes to finish the collections by Christmas, after which researchers will begin analyzing the samples. Previous research from the National Institute for Occupational Safety and Health has found that overall, firefighters tend to experience higher rates of certain cancers, including a particularly high rate of mesothelioma; however, relatively few women were included in the study.

Ruthann Rudel, a principal investigator on the Women Firefighter Biomonitoring Collaborative Study and research director at the Silent Spring Institute, said researchers will be examining the biological samples for three specific classes of chemicals. The first are flame retardants, which firefighters are exposed to via firefighting equipment and in the burning of everyday household items that contain the chemicals. The second are perfluorinated chemicals, also known as PFCs, which are used to make products more resistant to stains and water and are commonly found in sofas, mattresses, carpets and in firefighting materials. The third are products of combustion and diesel exhaust. (Buren noted that a firefighter can be stationed next to a fire truck exhaust for hours at a time as she or he pumps water onto a fire.) Rudel said that there is some evidence from animal studies that all three classes of chemicals may be contributors to mammary gland tumors.

As well as testing for those three groups of chemicals, Rudel said scientists will also use an innovative chemical analysis method known as Time of Flight to compare the firefighter and control group samples in an attempt to identify additional chemical exposures. Lastly, scientists will study the biological samples for early markers of a chemical exposure effect, such as changes in hormone levels.

“This study won’t tell us if these exposures caused breast cancer, but that there’s been an exposure to potential or likely carcinogens,” Rudel told me. “The study will tell us what chemicals are differentially exposed and that can give us clues as to how to reduce those exposures. …But I also don’t think we need to wait (to take protective action). We have a list of chemicals, we know they’re being used, we know women are exposed and we know they are likely breast carcinogens.”

Rudel noted that historically, most of what we understand about known human carcinogens came from the study of worker populations — “workers have been and continue to be guinea pigs in that way. That’s not a good thing, it’s just what happens,” she told me. And in fact, the women firefighters study could help pave the way for other groups of women workers to come forward with their own occupational exposure concerns.

“What’s so unique about this study is that although (the women firefighters) have support from the firefighter union and department, it’s the firefighters themselves who are making this study possible,” Rudel said.

So, at what point should the research start to shape policy? Nancy Buermeyer, policy implications advisor to the Women Firefighter Biomonitoring Collaborative Study and a senior policy strategist at the San Francisco-based Breast Cancer Fund, said the study results could contribute to a number of advocacy efforts, such as those aimed at better protecting firefighter health as well as more long-term activities aimed at reforming federal chemical regulations. Specifically, Buermeyer noted that the federal Toxic Substances Control Act of 1976, which provides the U.S. Environmental Protection Agency with some authority to require the reporting and testing of certain chemicals, is in desperate need of reform. Though advocates such as Buermeyer face a serious uphill battle and a very rich opponent.

“The chemical industry is extremely well resourced,” she told me. “But that’s why studies like this are so important — because the only thing that combats that kind of (industry) money is public outrage. …Being able to demonstrate with solid, strong evidence the levels of carcinogens in a population like firefighters is going to have a big impact on the public. Firefighters are extremely well respected and loved by the public and they can bring awareness to this issue in general.”

Buermeyer added that considering the current dearth of research on women and occupational exposures, she hopes the firefighter study will jumpstart additional research on work-related threats to women’s health. Buren also hopes the study will spur discussions on what can be done to better protect women and all firefighters’ health — “this is the beginning of something locally that will hopefully go globally,” she said.

During my conversation with Buren, she talked at length about her love for firefighting — “it’s a wonderful job, I love it. There’s times I can’t believe how lucky I am,” she said. As a firefighter, Buren said, you don’t stop to think about your fear, you just do your job. But cancer is a different story.

“For firefighters, cancer is really hard to look at and talk about, but we can’t not talk about it,” she said. “There is a fear. I don’t want it to be me and I don’t want it to keep happening to (my co-workers). We need to face it.”

To learn more about the Women Firefighter Biomonitoring Collaborative Study, visit http://womenfirefighterstudy.com.

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for more than a decade.